Plasticized properties of poly (lactic acid) and triacetine blends

Systematically investigations of the plasticizing effects of triacetine (TAc) on crystallization, chain mobility, microstructure, and tensile properties of the Poly (lactic acid)/triacetine (PLA/TAc) blends are reported. A new transition hump was observed on the tan δ curve of PLAxTAcy specimens at temperatures ranging from −80 to −20°C. Thermal, wide angle X‐ray diffraction (WAXD) and dynamic mechanical analysis properties of PLA and PLAxTAcy series specimens suggest that PLA and PLAxTAcy series specimens can hardly crystallize by cooling the melt in room temperature. However, significant recrystallization of α form PLA crystals was found during the annealing processes of PLAxTAcy series specimens. Some “less perfect” β form PLA crystals were found as the TAc contents of PLAxTAcy specimens reach 30 wt %. Further morphological analysis show that the inherent brittle deformation behavior of the PLA specimen was successfully transformed into relatively ductile fracture behavior after blending sufficient but optimum amounts of TAc in PLA resins. Possible reasons accounting for this interesting recrystallization, thermal, microstructure and tensile properties of PLAxTAcy specimens are proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009